1. Field of the Invention
The present invention relates broadly to a process of metering one or more concentrated chemical solutions with a metered amount of water and statically mixing the components together in an inline, static mixer to produce a diluted working solution which is fed to an automatic film processing machine on demand from such machine. In particular, the present invention relates to such a process in which the concentrated chemical solutions and water are automatically diluted and mixed together to form a relatively small amount of diluted working solution called for by the processing machine, and the proper amount of working solution is then fed to the processing machine in the specific amounts called for by the processing machine, with no intermediate storage of the diluted working solution other than the amount of working solution contained in the flow conduits that deliver the diluted working solution to the processing machine.
2. State of the Art
The present invention as mentioned above relates generally to apparatus and processes for measuring predetermined amounts of concentrated chemical solution and mixing the concentrated chemical solutions with a measured amount of water in an inline, static mixing device to produce a diluted solution which is delivered directly to an automatic film processing machine upon demand of the processing machine. In typical, automatic processing machines, such as used in processing photographic film in the fields of radiology, lithography and microfilm, the film negatives and positives are transported by a series of rollers through tanks within the processing machines that contain developer, fixer, wash and other solutions for the purpose of developing a latent image on the film.
During the development of the latent image on the film, the solutions contained in the various treatment tanks in the automatic processing machine become depleted in their chemical strength by means of the chemical reactions taking place with the films being processed, as well as by oxidation or other time dependent means of deterioration. This depletion of chemical strength and otherwise loss of efficacy that would result requires that the chemicals in the tanks of the processing machine be replenished with fresh chemicals. The treatment tanks in automatic processing machines are customarily replenished with relatively small, measured amounts of replenishment chemicals, generally in quantities of from about 80 to 120 cubic centimeters.
There are generally two methods used in the prior art for replenishing chemicals in the treatment tanks of the automatic processing machines. In the first method, a supplier who maintains or services the machines makes scheduled service calls for the purpose of keeping the storage containers associated with the processing machines properly filled with diluted chemical solutions. Concentrated chemicals are generally incompatible and cause unwanted precipitation and other reactions if mixed together in their concentrated state. Thus, the supplier must supply diluted chemical solutions for use in the day-to-day operation of the automatic processing machines.
This diluted, working solution must be stored in containers in the vicinity of the processing machine. The diluted, working solution itself is mixed at a remote site in batches generally of up to 1000 gallons or more at a time and filled into containers (typically five gallons each) to be transported to the site of the automatic processing machine. This process is extremely labor intensive and carries high transportation and delivery costs. In addition, since the mixing of the diluted, working solutions is often done by manual procedures, it is subject to human error and can be very inaccurate. The diluted, working solutions are commonly stored at the site of the automatic processing machines in containers that vary in size from five to eighty gallons or more. This causes undue hazards of on site storage of rather large quantities of chemicals and requires intensive regulatory compliance.
In the second general method of providing replenishment chemicals for the day-to-day operation of the automatic processing machine, the chemicals are supplied in concentrated form in prepackaged configurations that are to be mixed with a preset amount of fresh water to produce a diluted, working solution. This eliminates the storage of quantities of diluted, working solutions in excess of 5 to 10 gallons inasmuch as the prepackaged chemicals can be sized so as to produce such an amount. However, means must be provided for handling the concentrated chemicals and mixing the concentrated chemicals with a preset amount of fresh water. The prepackaged chemicals must be mixed with the proper amount of water in a mixer and the diluted solution is then stored in a suitable container.
There are many disadvantages associated with both of the general methods mentioned above. Both methods require mixing and storing a relatively large amounts of working solutions at least as compared to the small amount of such solution required to supply the cyclic demand of the processing machine. Anywhere from 10 to 80 or more gallons of working solution are generally stored at the site of the processing machine to supply a demand of approximately 100 cubic centimeters per cycle of the processing machine. On site storage of the relatively large amounts of chemicals presents problems of unnecessary hazards, require sizable storage space, present a problem with fumes and regulatory compliance procedures must be strictly followed.
Further, mixing of chemical materials as is required in both of the general methods as discussed above necessitates special mixing equipment such as tanks, mechanical mixers, high volume measuring equipment and relatively large storage space. The mixing becomes inaccurate because the measurements are done by hand. Thus it is subject to human error. It is also labor intensive and subject to relatively high costs. Off site mixing, as mentioned previously, requires storage and transportation of delivery containers and relatively large amounts of diluted chemicals. Transportation of the diluted chemicals is very costly as is the manual delivery and handling of the containers used to transport the diluted chemicals. Common to both of the general procedures discussed previously, the working solutions of the diluted chemicals are unstable and subject to decomposition with time. Oxidation and other modes of decomposition begin immediately following the mixing of the diluted chemicals. Working solutions are at their full strength and potency when used a short time after being mixed. The efficacy of the chemical components of the working solutions are greatly reduced with time following the mixing of the solutions.
Two prior art patents have been issued relating to methods and apparatus for replenishing chemical solutions in photographic processing machines. In U.S. Pat. No. 3,877,682 apparatus is disclosed for automatically measuring and mixing a predetermined quantity of two or more chemicals to form a working solution to be used in replenishing the chemical solutions in the treatment tanks of automatic photographic processors. The measuring and mixing are accomplished by using a single measuring chamber to measure all chemicals as well as water. The chamber drains into a mixing tank where the contents are mixed by means of a mixing pump. Following the mechanical mixing in the mixing tank, the mixed, diluted solutions are pumped into holding tanks. This method is impractical for several reasons. The method requires filling and emptying of the measuring chamber many times. For example, with chemical formulas for developer solutions in present use, the chamber would have to be filled 74 times to measure the water, 34 times for measurement of one component of the developer chemicals, and one time each for measurements of the second and third components of the developer chemicals. This is a total of 110 filling and dumping cycles of the measuring chamber to achieve a proper mix for the diluted, working solution. The amount of diluted, working solution produced is many times over the amount per cycle of working solution required for the photographic processing machine and requires storage of the excess, bulk supply of working solution.
The second patent, U.S. Pat. No. 3,822,723, discloses an apparatus for controlling make-up and addition of replenishment solution to a photographic processing machine. The device of this patent requires electronic input from sources reading percent of film exposure, replenishment rates, film size and time lapse. Based on this information, various chemical materials are fed directly into the various treatment tanks in the processing machine rather than being mixed together in a dilute, working solution that is added to the treatment tanks. This method is completely impractical with the customary processing machines which have no means of producing the electronic input relative to percent of film exposure, replenishment rates, film size and time lapse. The customary processing machines to which the present invention is directed require cyclic additions of predetermined, premixed amounts of diluted, working solution to the treatment tanks in the processing machine.
3. Objectives
A principal objective of the invention is to provide novel apparatus and procedures for automatically and accurately measuring and proportioning predetermined amounts of two or more concentrated chemical components and water. The chemical components and the water are mixed together in a static inline mixer that requires no mechanical mixer or other mixing mechanism. The chemicals and water are statically mixed to make one or more working solutions, and the working solutions are supplied directly to a processing machine upon demand from the processing machine in the relatively small amounts required by the processing machine. It is to be noted that although this invention is suited to supply chemical mixtures to automatic photographic film processing machines, it is also suited to many other types of chemical processes which require proportioning and mixing of chemical components.
A particular object of the present invention is to provide a relatively inexpensive system including apparatus and processes for mixing concentrated chemicals and water in small quantities to be delivered either directly to a photographic processing machine or through appropriate feed conduits to the processing machine upon demand from the processing machine.
An additional object of the present invention is to provide such a system and method in which concentrated chemicals are stored in relatively small storage containers within or adjacent to the processing machine, and as the processing machine calls for small quantities of diluted chemicals for replenishment of the working chemical solutions in the processing machine, the small quantities of diluted chemicals are produced in-situ by measuring or metering quantities of concentrated chemicals and water, mixing the chemicals and water immediately in static inline mixing devices and delivering the small quantities of diluted chemicals to the working chemical solutions in the processing machine either by directly adding the diluted chemicals to the treatment tanks containing the working chemical solutions or by feeding the diluted chemicals to the treatment tanks through feed conduits linking the inline static mixing devices and the treatment tanks of the processing machine.